Early on a Tuesday morning last fall, Ronnie O’Sullivan was running through the woods near his home, in Chigwell, Essex, northeast of London. It was damp and muddy, England in November. O’Sullivan, who is thirty-nine, loves the anonymity of running. About ten years ago, he discovered that it was one thing that truly takes him out of himself—more than the drink and the drugs and the antidepressants—and suspends the otherwise unavoidable fact that he is the most talented snooker player of all time. At the age of eleven, O’Sullivan was making good money in the sport, and in the past three decades he has won five World Championships and set a number of records while enduring a bewildering odyssey of breakdowns, addictions, and redemptions, largely precipitated by the imprisonment of his father, whom he loves, for murder. O’Sullivan is frequently described as a genius. But he does not see how this can be so. Most days, he feels like a fraud. His game comes only in fits and starts. He wins because the others lose. He has wondered for a long time whether he would be happier doing something else. He has moved nine times in the past ten years. ... Snooker’s civilized appearance belies its vicious and enervating nature. A snooker table is three times larger than a pool table and its pockets are an inch smaller. Even the most basic shot is a concatenation of foresight, friction, and various Newtonian laws. Players seek to control where at least two balls are going: the red or colored “object” ball, preferably toward a pocket; and the white ball, its rate of braking and spin carefully calibrated, either to stop near another object ball, so the process can begin again, or to continue toward some hostile district of the table, from where the opponent will be unlikely to score. The best players string together thirty shots in a row, in a hushed environment of thick carpet and dinner suits.